This study paid high attention to the biogas utilization in small
size pig farms. Underutilization of the produced biogas results in
the unused biogas released to the atmosphere. Moreover, there
are almost no H2S removal units in practice, mainly due to the lack
of awareness of the H2S toxicity as well as the lack of information
of the H2S removal technologies. Apart from the current use of biogas
for cooking, to provide heat for piglet heating and, to a limited
extent, to provide direct shaft work such as the water pump, the
potential of biogas for electricity generation was considered.
In this study, H2S removal by 2% potassium iodide (KI) impregnated
activated carbon adsorption was selected and introduced to
a biogas-to-electricity generation system set-up in a small pig farm
in Thailand. With the average inlet H2S concentration of about
2400 ppm to the adsorption unit, the adsorption tests showed that
the H2S removal efficiency could reach 100%. For the breakthrough
capacity of each batch (of two kilograms fresh adsorbent), the time
to reach 50 ppm for the best conditions used was in average 35 h,
which is equivalent to the adsorption capacity of 0.062 kg of H2S/
kg of adsorbent.